A patent document 1 described below is disclosing a disposable container filled with a material for dental treatment. On other words, the disposable container is filled with the material for dental treatment in an amount sufficient for the use of one time and is, usually, discarded after the use of one time. The container is provided with a cylindrical body portion, and has a nozzle formed at a front end of the body portion and a piston contained in the body portion. Before the material is being filled, the piston is disposed on the front end side of the body portion, i.e., is disposed on the nozzle side.
To pour the material into the disposable container, use is made of a stock container which contains the material. The stock container is provided with a port in which the nozzle of the disposable container is to be inserted, and the nozzle of the disposable container is set into a push-in port. To pour the material into the disposable container, the material contained in the stock container is pressurized and is poured into the disposable container through the nozzle and, at the same time, the piston in the container moves back being pushed by the material that is poured. After the piston is moved back to a predetermined position, the pouring is discontinued and the disposable container is thus filled with the material.
At the start of pouring the material that is to be filled, the piston is disposed at the front end of the body portion of the disposable container so that no air remains in the container.
In other words, if the material is poured from the rear end side of the body portion, the materials flows from the opening on the rear end side toward the filling surface on the front end side inevitably trapping the air on the way of flowing through the body portion and flowing into the filling surface. On the other hand, by disposing the piston at the front end position of the body portion of the disposable container, pouring the material into the container through the nozzle, maintaining the filling surface in close contact with the front end surface of the piston, and moving the piston back in proportion to an increase in the amount of filling, it is allowed to greatly decrease the amount of the air that remains in the material that is filled. Thus, upon eliminating the air that remains and discontinuing the pouring of the material at a predetermined position to where the piston has moved back, it is allowed to pour the material in a correct amount.